The objective of these studies is to evaluate the potential of environmental chemicals to affect female reproductive function. These studies compare toxic effects at high and low levels of exposure. As a model compound for these experiments, we are studying the effects of Kepone on female reproductive function. The toxicity of these compounds is evaluated using a broad spectrum of toxic indicators. Since these effects, and the effects of other environmental compounds, may be mediated through their estrogenic or other hormonal activity, we have established a number of criteria which indicate hormone activity. Uterine, ovarian and pituitary function are studied in morphological and endocrinological studies after Kepone exposure. Fertility and reproduction are also evaluated in treated females and in offspring exposed perinatally to Kepone. Morphological studies include light and scanning electron microscopy, hormone and xenobiotic autoradiography, and histochemistry. Biochemical studies include hormone radioimmunoassay and hormone receptor assays. It is anticipated that these studies will help establish the mechanism of reproductive toxicity of compounds such as Kepone. Such data should also leat to more efficient and accurate testing systems in reproductive toxicology.